1. Field of the Invention
This invention relates to aircraft hangars and, more particularly, to hangars that are mobile and adjustable for accommodating different aircraft.
2. Description of the Related Art
Additional aircraft hangars and work docks are commonly desired by most aircraft operators and airport authorities. Unfortunately, the construction costs for new hangars and the amount of available space around an airport often prevents their construction. Furthermore, the availability of hangars is a factor that substantially affects the aircraft maintenance operations and aircraft scheduling for an airline company.
Airlines typically have two distinct maintenance operations modesxe2x80x94a line maintenance and a check maintenance modexe2x80x94that perform both scheduled and non-routine maintenance actions. Because an aircraft is used daily, it needs to be in a continual state of serviceability. Each aircraft in the airline company""s fleet is assigned a routing schedule. Once assigned, the smooth operation of the airline company depends on the aircraft being at the gate in a serviceable condition. If it is not, the schedule of the aircraft in the fleet can be affected.
Typically, each aircraft operating in the fleet has scheduled maintenance tasks performed during regular overnight visits. The completion of these tasks is of utmost importance to the airline company. The performance of these maintenance tasks at night and during inclement weather conditions often slows down the production of the workers. As a result, the maintenance tasks on the aircraft may not be completed.
Line maintenance operations are driven by the airline company""s schedule. Aircraft are assigned to routes dependant on the projected passenger capacity for a given time period or season. For a particular season, a narrow-body aircraft may be required while the next season may require a wide-body aircraft. Also, the number of aircraft at a location may change with different seasons. These two variables require maintenance to be carried out at different facilities at different times of the year. If there are inadequate or insufficient hangar facilities at an airport, the aircraft may need to be re-routed to an airport with adequate facilities so that the maintenance service may be completed.
Factors that make up non-routine maintenance include items that suddenly break or need repair in the normal course of operation. Some of these items can be deferred while some require immediate replacement or repair before the aircraft can be dispatched. Many of these items involve procedures that require many man-hours to complete. They also may require a significant level of disassembly, rework, and re-assembly which, ideally, should be completed at a maintenance base inside a hangar. In many instances, these repairs must be performed outside at airports without hangars.
In some instances, the aircraft may be in service with a particular component that is inoperative. Components operating under these programs, known as a MEL (minimum equipment list) or CDL (configuration deviation list) programs, have time restrictions that specifically limit how long the aircraft can operate in this condition. This puts the aircraft in a state known as xe2x80x9cdegraded serviceability.xe2x80x9d If the time limit expires and the condition has not been repaired, the aircraft is considered unserviceable.
The repair or replacement tasks for aircraft operating under MEL or CDL programs are assigned to a line station as the aircraft continues on its normal routing. In the early stages of the time restriction, lesser priority is usually given to those deferrals due to weather conditions or lack of hangar availability. As the deadline nears, the importance of performing these tasks increases. Often at the end of the deferral period, the aircraft is rerouted to a line maintenance base that has a hangar.
One of the factors in deciding to which line station a task will be assigned is whether or not the station has in stock the aircraft part that is inoperative. When the task is deferred due to weather or lack of hangar availability, utilization of the parts inventory is degraded. Many times when the aircraft is later re-routed to a line maintenance base for repair at the end of the deferral period, the local storage facility at the line station maintenance base may not have the particular part in stock. The problem of deferral may have occurred recently on other aircraft, and the part has not yet been restocked. This can lead to the situation where the aircraft is placed out of service, known as AOS. Had the previously assigned line maintenance stations been available with adequate facilities to change the part for which they were allocated, the aircraft would have been returned to the state of full air worthiness sooner.
For all of these reasons, availability or lack of adequate hangar facilities impacts an airline company""s initial decision to provide air transportation to an airport. If the airport authorities can offer hangars to airlines, they can attract and maintain airline service. Also, if affordable hangars are available to an airline company, utilization of their fleets can be maximized.
What is needed is an aircraft hangar that is relatively inexpensive to purchase, adjustable for use with different sized aircraft, and moveable to different areas on the airport.
It is the object of the invention to provide a mobile aircraft hangar.
It is another object of the invention to provide such an aircraft hangar for workers performing routine and non-routine maintenance services on an aircraft.
It is a further object of the invention to provide such an aircraft hangar that is adaptable for working on different sized aircraft, and on different sections on the aircraft.
These and other objects are met by a mobile aircraft hangar, disclosed herein, designed to provide a temporary, enclosed working environment for workers performing a wide range of routine and non-routine maintenance services on an aircraft. The aircraft hangar includes a housing assembly designed to enclose various sections of a large aircraft including, but not limited to, the engines and pylon assemblies, various wing sections, the horizontal stabilizer and elevator assemblies, the nose and doors. The housing assembly includes one vertical end wall and two opposite vertical side walls connected together along their adjacent edges to form a three-sided enclosing structure. Located opposite the vertical end wall is large main opening, which allows a desired section of the aircraft to be positioned inside the central work area located inside the hangar assembly during use. A set of adjustable doors is placed over the main opening, which may be selectively opened or closed to create a closed work environment around the desired section of aircraft positioned inside the work area.
The housing assembly includes a plurality of optional moveable floor panels that can be arranged in different configurations inside the housing assembly for supporting workers working on different sections of the aircraft. The moveable floor panels also allow various aircraft components to be easily inserted or removed from the aircraft. The housing assembly may also include an optional housing assembly lifting means that enables the housing assembly to be selectively raised over the chassis described below, so that the housing assembly may be placed around an elevated section of an aircraft. Further, the housing assembly may include a rear door and exterior articulating stairs to provide ingress and egress from the housing assembly.
The housing assembly is attached to a rigid chassis. The chassis includes a plurality of optional wheels and a steering means that enable it to be easily maneuvered around an aircraft parked in the repair area. The chassis also includes an optional engine, electric generators, hydraulic pumps, and environmental controls to provide for the workers a self-sustained work environment.
Disposed above and extending over the housing assembly is a roof assembly design to fully cover the central work area. In the preferred embodiment, the roof assembly is supported by a roof lifting assembly that enables the roof assembly to be selectively raised and lowered over the housing assembly so that different sections of the aircraft may be placed inside the housing assembly. The roof lifting assembly includes two vertically aligned, rear jack screws located near the two rear corners and two vertically aligned, front jack screws located aft of the mid-line axis of the housing and roof assembles. The jack screws are all coupled to at least one motor which is used to selectively raise and lower the roof assembly over the housing assembly.
In the preferred embodiment, the roof assembly is spaced apart from and disposed above the housing assembly, thereby creating an upper space therebetween. By positioning the front jack screws just aft of the mid-line axis of the housing and roof assemblies, the sections of the upper space, located on each opposite side wall that extends forward from the front jack screws to the main opening are unobstructed. During use, a horizontally aligned section of an aircraft, such as a wing or the horizontal stabilizer, may be extended between the two unobstructed sections of the upper space and positioned transversely through the hangar assembly. In another embodiment, the roof assembly may be rigidly attached to the housing assembly with a recessed opening formed on each side wall. The recessed openings are located directly across from each other to enable a wing or stabilizer to extend transversely across the housing assembly.
Located in the upper space between the roof assembly and the housing assembly and between the roof assembly and the adjustable doors, is an optional first sealing means designed to selectively close the upper space. The first sealing means is adjustable in length to accommodate different heights of the upper space. The first sealing means is also designed to conform to different shapes of sections of the aircraft placed therein. A second sealing means is also provided for each recessed opening to close off any gaps or openings created between the vertical side wall and the upper and lower surfaces of the wing or stabilizer extending through the recessed space. A third sealing means is provided along the top of the adjustable doors that extend upward to selectively close off any open space between the top of the doors and the lower surface of a wing or stabilizer extending through the main opening.